Thin film magnetic head structure, method of making same and thin film magnetic head

ABSTRACT

A thin-film magnetic head structure has a configuration adapted to manufacture a thin-film magnetic head configured such that a main magnetic pole layer including a magnetic pole tip on a side of a medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole tip so as to form a recording gap layer on the medium-opposing surface side, and a thin-film coil wound about the write shield layer or main magnetic pole layer are laminated. The magnetic pole tip of the main magnetic pole layer includes an even width portion having a substantially even width along an extending direction.

This application is a continuation of U.S. Parent application Ser. No.10/985,891, filed Nov. 12, 2004, the entire contents of which are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a thin-film magnetic head structure formanufacturing a thin-film magnetic head which performs magneticrecording operations by perpendicular recording, a method ofmanufacturing the same, and a thin-film magnetic head.

2. Related Background Art

In recent years, the areal density in hard disk drives has beenincreasing remarkably. Recently, the areal density in hard disk driveshas reached 160 to 200 GB/platter in particular, and is about toincrease further. Accordingly, thin-film magnetic heads have beenrequired to improve their performances.

In terms of recording schemes, thin-film magnetic heads can roughly bedivided into those for longitudinal recording in which information isrecorded in a (longitudinal) direction of a recording surface of a harddisk (recording medium) and those for perpendicular recording in whichdata is recorded while the direction of recording magnetization formedin the hard disk is perpendicular to the recording surface. As comparedwith the thin-film magnetic heads for longitudinal recording, thethin-film magnetic heads for perpendicular recording have beenconsidered more hopeful, since they can realize a much higher recordingdensity while their recorded hard disks are less susceptible to thermalfluctuations.

Conventional thin-film magnetic heads for perpendicular recording aredisclosed, for example, in U.S. Pat. No. 6,504,675, U.S. Pat. No.4,656,546, U.S. Pat. No. 4,672,493, and Japanese Patent ApplicationLaid-Open No. 2004-94997.

Meanwhile, when thin-film magnetic heads for perpendicular recordingrecord data onto areas in inner and outer peripheries of a hard disk, amagnetic pole tip disposed on the side of a medium-opposing surface(also referred to as air bearing surface, ABS) opposing the recordingmedium (hard disk) yields a certain skew angle with respect to a datarecording track. In perpendicular magnetic recording heads (hereinafteralso referred to as “PMR”) having a high writing capability, the skewangle has caused a problem of so-called side fringe in which unnecessarydata are recorded between adjacent tracks. The side fringe adverselyaffects the detection of servo signals and the S/N ratio of reproducedwaveforms. Therefore, in conventional PMRs, the magnetic pole tip on theABS side in the main magnetic pole layer has a bevel form graduallynarrowing in width toward one direction (see, for example, JapanesePatent Application Laid-Open Nos. 2003-242607 and 2003-203311 in thisregard).

SUMMARY OF THE INVENTION

In PMRs in which the magnetic pole tip on the ABS side in the mainmagnetic pole layer has a bevel form, the width of the magnetic pole(hereinafter referred to as tip width) is not sufficiently uniform andthus is uneven along the length of the main magnetic pole layer.Therefore, when the above-mentioned magnetic pole tip of the mainmagnetic pole layer formed on the wafer is cut at a predeterminedposition so as to define the ABS, the tip width of the ABS may varydepending on the cut position. Hence, there have been cases where theconventional PMRs yield large deviations in the track width (recordingtrack width) in the ABS among products.

In order to overcome the problem mentioned above, it is an object of thepresent invention to provide a thin-film magnetic head structure whichperforms track width control with a high accuracy, a method ofmanufacturing the same, and a thin-film magnetic head.

For solving the above-mentioned problem, in one aspect, the presentinvention provides a thin-film magnetic head structure adapted tomanufacture a thin-film magnetic head configured such that a mainmagnetic pole layer including a magnetic pole tip on a side of amedium-opposing surface opposing a recording medium, a write shieldlayer opposing the magnetic pole tip so as to form a recording gap layeron the medium-opposing surface side, and a thin-film coil wound aboutthe write shield layer or main magnetic pole layer are laminated;wherein the magnetic pole tip of the main magnetic pole layer includesan even width portion having a substantially even width along anextending direction intersecting the medium-opposing surface.

In this thin-film magnetic head structure, a main magnetic pole layercomprising a magnetic pole tip including an even width portion isformed. Therefore, if the main magnetic pole layer is cut at the evenwidth portion of the magnetic pole tip when defining the medium-opposingsurface (ABS), the ABS attains the same width with a high accuracy.Hence, when this thin-film magnetic head structure is used for making athin-film magnetic head, the latter can be obtained with a track widthwhich is controlled with a high accuracy.

Preferably, the thin-film magnetic head structure further comprises abase insulating layer including a magnetic pole forming depressionsunken into a form corresponding to the main magnetic pole layer, themagnetic pole forming depression including a very narrow groove parthaving a substantially even width, the even width portion being formedin the very narrow groove part of the magnetic pole forming depression.In this case, the main magnetic pole layer is formed so as to beembedded in the magnetic pole forming depression.

Preferably, the magnetic pole forming depression includes a pair ofvariable width depressions continuously extending from respective endparts of the narrow groove part, each of the variable width depressionshaving a width increasing in a direction away from the narrow groovepart; whereas the narrow groove part has such a width and length that aplating material grown in the variable width depression when forming themain magnetic pole layer by plating within the magnetic pole formingdepression fills the narrow groove part without a gap. In this case, theplating material grown in the individual variable width depressions ofthe magnetic pole forming depression enters the narrow groove part fromboth ends thereof, whereby the narrow groove part can be filled morereliably.

Preferably, the even width portion has a length of 0.3 μm to 1.2 μmalong the extending direction thereof, and a width of 0.2 μm or less.

It will be preferred if the main magnetic pole layer has an end facejoint structure where respective end faces of the magnetic pole tip anda yoke magnetic pole part having a size greater than that of themagnetic pole tip are joined to each other. The conventional PMRs havebeen problematic in that they cause a phenomenon known as pole erasureby which data recorded beforehand on a hard disk is erased wheninformation is further recorded at a high density. The pole erasure is aphenomenon in which, after data is written on a recording medium (harddisk) having a high maximum coercivity Hc, a leakage magnetic flux flowsfrom the ABS to the hard disk even when no write current flows through athin-film coil, thereby erasing the other data. The end face jointbetween the magnetic pole tip and yoke magnetic pole part can preventthe pole erasure from occurring.

Preferably, the narrow groove part is formed such that a groove widthintersecting the length thereof gradually decreases along the depththereof. In this case, the main magnetic pole layer including abevel-formed magnetic pole tip is obtained.

In another aspect, the present invention provides a method ofmanufacturing a thin-film magnetic head structure adapted to manufacturea thin-film magnetic head configured such that a main magnetic polelayer including a magnetic pole tip on a side of a medium-opposingsurface opposing a recording medium, a write shield layer opposing themagnetic pole tip so as to form a recording gap layer on themedium-opposing surface side, and a thin-film coil wound about the writeshield layer or main magnetic pole layer are laminated; the methodcomprising the step of forming the magnetic pole tip of the mainmagnetic pole layer such that at least a part of the magnetic pole tipbecomes an even width portion having a substantially even width along anextending direction.

This method of manufacturing the thin-film magnetic head structure formsa main magnetic pole layer comprising a magnetic pole tip including aneven width portion. Therefore, if the main magnetic pole layer is cut atthe even width portion of the magnetic pole tip when defining themedium-opposing surface (ABS) in the thin-film magnetic head made bythis manufacturing method, the ABS attains the same width with a highaccuracy. Hence, when the thin-film magnetic head structure made by thismanufacturing method is used for making a thin-film magnetic head, thelatter can be obtained with a track width which is controlled with ahigh accuracy.

It will be preferred if the step of forming the magnetic pole tip of themain magnetic pole layer includes the steps of forming a base insulatinglayer including a magnetic pole forming depression sunken into a formcorresponding to the main magnetic pole layer, the magnetic pole formingdepression including a narrow groove part having a substantially evenwidth; and filling the magnetic pole forming depression with a magneticmaterial so as to form the main magnetic pole layer and form the evenwidth portion within the narrow groove part.

Preferably, the magnetic pole forming depression includes a pair ofvariable width depressions continuously extending from respective tipsof the narrow groove part, each of the variable width depressions havinga width increasing in a direction away from the narrow groove part;whereas, when forming the even width portion by plating within thenarrow groove part, a plating material grown in the variable widthdepression fills the narrow groove part without a gap. In this case, theplating material grown in the individual variable width depressions ofthe magnetic pole forming depression enters the narrow groove part fromboth ends thereof, thereby filling the narrow groove part.

It will be preferred if the step of forming the main magnetic pole layerincludes the steps of forming an end-face-equipped magnetic pole layerhaving an in-depression end face exposed into a region other than thenarrow groove part in the magnetic pole forming depression of the baseinsulating layer; and forming a joining magnetic pole layer joined tothe in-depression end face in the end-face-equipped magnetic pole layer.

When forming the main magnetic pole layer, the magnetic material fillingthe narrow groove part in the magnetic pole forming depression may bemade thicker than the magnetic material filling a region other than thenarrow groove part.

In still another aspect, the present invention provides a thin-filmmagnetic head configured such that a main magnetic pole layer includinga magnetic pole tip on a side of a medium-opposing surface opposing arecording medium, a write shield layer opposing the magnetic pole tip soas to form a recording gap layer on the medium-opposing surface side,and a thin-film coil wound about the write shield layer or main magneticpole layer are laminated; wherein the magnetic pole tip of the mainmagnetic pole layer includes an even width portion having asubstantially even width along an extending direction.

In this thin-film magnetic head, a main magnetic pole layer comprising amagnetic pole tip including an even width portion is formed. Therefore,the width in the medium-opposing surface (ABS) is controlled with a highaccuracy. Hence, the track width is controlled with a high accuracy inthis thin-film magnetic head.

The present invention will be more fully understood from the detaileddescription given hereinbelow and the accompanying drawings which aregiven by way of illustration only, and thus are not to be considered aslimiting the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of the thin-film magnetic head structure inaccordance with an embodiment of the present invention, in which FIG. 1Ais a sectional view taken along a direction intersecting a thin-filmcoil, and FIG. 1B is a sectional view showing the ABS when cut at theABS;

FIG. 2 is a view showing an insulating layer, in which FIG. 2A is a planview, and FIG. 2B is a sectional view taken along the line B-B of FIG.2A;

FIG. 3 is a view showing a major part of FIG. 2 under magnification, inwhich FIG. 3A is a plan view, FIG. 3B is a sectional view taken alongthe line B-B of FIG. 3A, and FIG. 3C is a sectional view showing themajor part in FIG. 3B under magnification;

FIG. 4 is a view showing a main magnetic pole layer after being cutalong the ABS, in FIG. 4A is a perspective view, and FIG. 4B is asectional view taken along the line B-B of FIG. 4A;

FIG. 5 is a plan view or sectional view in a step of the manufacturingmethod, in FIG. 5A is a plan view, FIG. 5B is a sectional view takenalong the line B-B of FIG. 5A, FIG. 5C is a plan view showing a majorpart of FIG. 5A under magnification, and FIG. 5D is a sectional viewtaken at the ABA in FIG. 5B;

FIG. 6 is a plan view or sectional view in a step subsequent to FIG. 5,in which FIG. 6A is a plan view, FIG. 6B is a sectional view taken alongthe line B-B of FIG. 6A, FIG. 6C is a plan view showing a major part ofFIG. 6A under magnification, and FIG. 6D is a sectional view taken atthe ABS in FIG. 6B;

FIG. 7 is an enlarged view of a major part in FIG. 6, showing theconfiguration of a coating formed in a narrow groove part of FIG. 6D;

FIG. 8 is a plan view or sectional view in a step subsequent to FIG. 6,in which FIG. 8A is a plan view, FIG. 8B is a sectional view taken alongthe line B-B of FIG. 8A, FIG. 8C is a plan view showing a major part ofFIG. 8A under magnification, and FIG. 8D is a sectional view taken atthe ABS in FIG. 8B;

FIG. 9 is a plan view or sectional view in a step subsequent to FIG. 8,in which FIG. 9A is a plan view, FIG. 9B is a sectional view taken alongthe line B-B of FIG. 9A, FIG. 9C is a plan view showing a major part ofFIG. 9A under magnification, and FIG. 9D is a sectional view taken atthe ABS in FIG. 9B;

FIG. 10 is an enlarged view of a major part in FIG. 9, showing theconfiguration of a coating formed in a narrow groove part of FIG. 9D;

FIG. 11 is a sectional view in a step subsequent to FIG. 9, in whichFIG. 1A is a sectional view taken along a direction intersecting thethin-film coil, and FIG. 1B is a sectional view showing the ABS when cutat the ABS;

FIG. 12 is a sectional view in a step subsequent to FIG. 11, in whichFIG. 12A is a sectional view taken along a direction intersecting thethin-film coil, and FIG. 12B is a sectional view showing the ABS whencut at the ABS;

FIG. 13 is a sectional view in a step subsequent to FIG. 12, in whichFIG. 13A is a sectional view taken along a direction intersecting thethin-film coil, and FIG. 13B is a sectional view showing the ABS whencut at the ABS;

FIG. 14 is an enlarged view of a major part showing the state of thenarrow groove part when a magnetic pole layer is formed in a cavity;

FIG. 15 is a plan view or sectional view in a step lead to FIG. 8, inwhich FIG. 15A is a plan view, FIG. 15B is a sectional view taken alongthe line B-B of FIG. 15A, FIG. 15C is a plan view showing a major partof FIG. 15A under magnification, and FIG. 15D is a sectional view takenat the ABS in FIG. 15B

FIG. 16 is a plan view or sectional view in a step subsequent to FIG.15, in which FIG. 16A is a plan view, FIG. 16B is a sectional view takenalong the line B-B of FIG. 16A, FIG. 16C is a plan view showing a majorpart of FIG. 16A under magnification, and FIG. 16D is a sectional viewtaken at the ABS in FIG. 16B;

FIG. 17 is a view showing a keyhole occurring in a conventional mainmagnetic pole layer;

FIG. 18 is a plan view showing a conventional method of manufacturing athin-film magnetic head, in which FIG. 18A and FIG. 18B show respectivestates before and after etching;

FIG. 19 is a plan view showing the main magnetic pole layer in aconventional thin-film magnetic head, in which FIG. 19A shows the mainmagnetic pole layer as set, and FIG. 19B shows the manufactured mainmagnetic pole layer;

FIG. 20 is a sectional view showing the conventional method ofmanufacturing a thin-film magnetic head, in which FIG. 20A shows a stateprovided with a photoresist, and FIG. 20B shows a state after thephotoresist is removed;

FIG. 21 is a sectional view showing the conventional method ofmanufacturing a thin-film magnetic head, in which FIG. 21A shows a stateprovided with another photoresist, and FIG. 21B shows a state after thephotoresist is removed;

FIG. 22 is a sectional view showing a different method of manufacturinga thin-film magnetic head structure, in which FIG. 22A, FIG. 22B, andFIG. 22C show first, second, and third steps, respectively;

FIG. 23 is a view showing the main magnetic pole layer after being cutalong the ABS, in which FIG. 23A is a perspective view, and FIG. 23B isa sectional view taken along the line B-B of FIG. 23A

FIG. 24 is a plan view of the main magnetic pole layer shown in FIG. 23;

FIG. 25 is a view showing an example of conventional thin-film magnetichead, in which FIG. 25A is a sectional view, and FIG. 25B is a frontview showing the ABS;

FIG. 26 is a sectional view of the thin-film magnetic head structure inaccordance with Modified Example 1, in which FIG. 26A is a sectionalview taken along a direction intersecting the thin-film coil, and FIG.26B is a sectional view showing the ABS when cut at the ABS;

FIG. 27 is a sectional view of the thin-film magnetic head structure inaccordance with Modified Example 2, in which FIG. 27A is a sectionalview taken along a direction intersecting the thin-film coil, and FIG.27B is a sectional view showing the ABS when cut at the ABS;

FIG. 28 is a sectional view of the thin-film magnetic head structure inaccordance with Modified Example 3, in which FIG. 28A is a sectionalview taken along a direction intersecting the thin-film coil, and FIG.28B is a sectional view showing the ABS when cut at the ABS;

FIG. 29 is a sectional view of the thin-film magnetic head structure inaccordance with Modified Example 4, in which FIG. 29A is a sectionalview taken along a direction intersecting the thin-film coil, and FIG.29B is a sectional view showing the ABS when cut at the ABS;

FIG. 30 is a view showing a mode of cavity;

FIG. 31 is a view showing a mode of cavity;

FIG. 32 is a view showing a mode of cavity;

FIG. 33 is a view showing a mode of cavity;

FIG. 34 is a view showing a mode of cavity; and

FIG. 35 is a view showing a mode of cavity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the present invention will be explainedwith reference to the drawings. Constituents identical to each otherwill be referred to with numerals identical to each other withoutrepeating their overlapping descriptions.

Configuration of Thin-Film Magnetic Head Structure

First, with reference to FIGS. 1 to 4, the configuration of thethin-film magnetic head structure in accordance with an embodiment ofthe present invention will be explained. FIG. 1 is a sectional view of athin-film magnetic head structure 300 in accordance with the embodimentof the present invention, in which FIG. 1A a sectional view taken alonga direction intersecting a thin-film coil, and FIG. 1B is a sectionalview showing the ABS when cut at the ABS.

The thin-film magnetic head structure 300 has a configuration adapted tomanufacture a magnetic head for perpendicular recording. The thin-filmmagnetic head structure 300 is formed on a substrate which is notdepicted, and yields a thin-film magnetic head 300A in the presentinvention when cut at an ABS 30 which is a medium-opposing surfaceopposing a recording medium (hard disk).

The thin-film magnetic head structure 300 comprises a substrate; areproducing head structure, laminated on the substrate, formanufacturing a reproducing head comprising an MR device(magnetoresistive device) or the like; and a recording head structurefor manufacturing a recording head. FIGS. 1A and 1B show the recordinghead structure laminated on the insulating layer 1, while omitting thesubstrate and the reproducing head structure.

The configuration of a major part of the recording head structure in thethin-film magnetic head structure 300 will be explained in thefollowing, whereas the configuration of the other parts will beexplained in manufacturing steps which will be set forth later. Eachconstituent in the recording head structure will be explained with thesame name and numeral before and after being cut at the ABS 30 unlessotherwise specified in particular. When distinguishing these states fromeach other, however, “′” will be added to the numeral referring to thestate after being cut at the ABS 30.

As shown in FIG. 1, the thin-film magnetic head structure 300 comprisesthe insulating layer 1, and a main magnetic pole layer 10, a recordinggap layer 24, a write shield layer 40, a back magnetic pole layer 51,and a thin-film coil 100 which are laminated on the insulating layer 1.

The insulating layer 1 is the base insulating layer in the presentinvention and is formed in a predetermined region on the substrate. FIG.2 is a view showing the insulating layer 1, in which FIG. 2A is a planview, and FIG. 2B is a sectional view taken along the line B-B of FIG.2A. FIG. 3 is a view showing a major part of FIG. 2 under magnification,in which FIG. 3A is a plan view, FIG. 3B is a sectional view taken alongthe line B-B of FIG. 3A and FIG. 3C is a sectional view showing themajor part in FIG. 3B under magnification. In the insulating layer 1,FIG. 2 shows a rectangular predetermined region centered at a cavity 2which will be explained later.

The insulating layer 1 is made of alumina (Al₂O₃) and has the cavity 2at a center part (hatched part in FIGS. 2A and 3A) on the side of asurface to be formed with a recording head. The cavity 2 is the magneticpole forming depression in the present invention, and is sunken into aform corresponding to the outer form of the main magnetic pole layer 10in order to form the main magnetic pole layer 10 in set dimensions andshape. Namely, as will be explained later in detail, the cavity 2 isformed earlier than the main magnetic pole layer 10, such that itsdimensions and shape including the depth d1 (about 0.25 μm to 0.35 μm,preferably 0.3 μm), width, and length coincide with assumed thickness,width, and length of the main magnetic pole layer 10. The cavity 2includes a very narrow groove part 3, a variable width depression 4, afixed width depression 5, and a protruded depression 6, whereas amagnetic material embedded therein forms the main magnetic pole layer10.

The very narrow groove part 3 is formed so as to define the track widthof the thin-film magnetic head, and has a structure adapted to improvethe recording density by reducing the track width. As shown in FIG. 3,the length of the narrow groove 3 is set to L1 (longer than a neckheight NH which will be explained later, i.e., L1>NH) such that the ABS30 can be secured in an intermediate part of the length. The groovewidth intersecting the length is W3 on the surface side, and is W4 onthe lower side, whereas the groove widths W3 and W4 are made narrowerthan the variable width depression 4 and fixed width depression 5 asmuch as possible, so as to yield a very narrow structure in order toimprove the recording density of the thin-film magnetic head. Also, thegroove width is gradually narrowing along the depth such that a magneticpole tip 11 which will be explained later has a bevel form. Namely, thegroove width W4 is smaller than the groove width W3 (W3>W4) in thenarrow groove part 3, so that the bevel angle θ shown in FIG. 3C becomesabout 7 to 12 degrees (e.g., 10 degrees).

The variable width depression 4 continuously extends from one end partof the very narrow groove part 3, whereas the protruded depression 6continuously extends from the other end part. Each of the variable widthdepression 4 and protruded depression (a pair of variable widthdepressions) gradually increases its groove width in the direction awayfrom the very narrow groove part 3. The variable width depression 4 isconnected to the fixed width depression 5 having a constant groovewidth. The distance from the boundary part between the variable widthdepression 4 and the very narrow groove part 3 to the ABS 30 will laterbecome the neck height NH.

As shown in FIG. 4, the main magnetic pole layer 10′ formed by using theabove-mentioned cavity 2 (as with the main magnetic pole layer 10 beforecutting) comprises a magnetic pole tip 11′ and a yoke magnetic pole part20′, whereas its surface on the side closer to the thin-film coil 100has a stepless flat structure. FIG. 4 is a view showing the mainmagnetic pole layer 10′ after being cut along the ABS 30, in which FIG.4A is a perspective view, and FIG. 4B is a sectional view taken alongthe line B-B of FIG. 4A. The main magnetic pole layer 10′ is formed soas to be embedded in the cavity 2.

The magnetic pole tip 11′ (as with the magnetic pole tip 11 beforecutting) is disposed at a position closer to the ABS 30 than is the yokemagnetic pole part 20′. The magnetic pole tip 11′ extends along adirection intersecting the ABS 30, and is formed with an even widthportion 12 throughout its length. The even width portion 12 is a partdefining the track width of the thin-film magnetic head in accordancewith the present invention, and has an even width of 0.1 μm throughoutthe length of the magnetic pole tip 11′.

The magnetic pole tip 11′ has a width determined by the very narrowgroove part 3. Along the ABS 30, the magnetic pole tip 11′ has a widthW1 on the side closer to the thin-film coil 100, and a width W2 on theside distant from the thin-film coil 100, thereby yielding a bevel formwhose width gradually narrows in the direction away from the thin-filmcoil 100 (W1>W2, whereas the width W1 is the track width; see FIG. 1).The magnetic pole tip 11′ has a narrow track width structure in whichthe above-mentioned W1 is narrowed in order to enhance the recordingdensity of data due to the thin-film magnetic head. The widths W1 and W2correspond to the groove widths W3 and W4 of the very narrow groove part3 in the cavity 2, respectively. The length of the magnetic pole tip 11′(distance from the ABS 30) corresponds to the neck height NH (which ison the order of 0.1 μm to 0.3 μm, preferably 0.15 μm in thisembodiment).

The yoke magnetic pole part 20′ is integrally formed with the magneticpole tip 11′ from the same magnetic material, and has a size (area)greater than that of the magnetic pole tip 11′. The yoke magnetic polepart 20′ comprises a variable width region 21 whose width graduallyincreases in the direction away from the ABS 30, and a fixed widthregion 22 having a constant width. The variable width region 21 isformed continuously from the magnetic pole tip 11′ on the side distantfrom the ABS 30. The fixed width region 22 is formed continuously fromthe variable width region 21 on the side distant from the ABS 30. At aposition distant from the ABS 30 than is the recording gap layer 24, thefixed width region 22 is magnetically connected to the back magneticpole layer 51.

Referring to FIG. 1 again, the recording gap layer 24 is interposedbetween the main magnetic pole layer 10 and a first shield part 41 ofthe write shield layer 40, which will be explained later, the insulatinglayer 31, and the back magnetic layer 51.

The write shield layer 40 comprises the first shield part 41, a secondshield part 42, and a third shield part 43. The first shield part 41 isformed so as to oppose the magnetic pole tip 11 of the main magneticpole layer 10 by way of the recording gap layer 24 on the ABS 30 side,whereby the neck height NH is determined by the distance from the ABS 30in a direction intersecting the ABS 30. The second shield part 42 isformed so as to connect with the first shield part 41 and back magneticpole layer 51 from the side closer to the thin-film coil 100, and has aheight equivalent to the thickness of the thin-film coil 100. The thirdshield part 43 is formed so as to connect with the second shield part 42and cover the thin-film coil 100 and a photoresist 101 by way of aninsulating layer 32.

The back magnetic pole layer 51 is connected to the yoke magnetic polepart 20 in a part distant from the ABS 30 than is the recording gaplayer 24. The back magnetic pole layer 51 is magnetically connected tothe second shield part 42, and forms a joint 44 together with the secondshield part 42.

By way of the recording gap layer 24 and the insulating layer 31, thethin-film coil 100 is formed so as to ride on the variable width region21 and fixed width region 22 of the yoke magnetic pole part 20′. Thethin-film coil 100 is wound in a planar spiral about the write shieldlayer 40 while being insulated therefrom by the insulating layers 31,32. The thin-film magnetic head 100 may be changed to a helical coilspirally wound about the main magnetic pole layer 10 as appropriate.

Thus configured thin-film magnetic head structure 300 is cut so as toform the ABS 30 in an intermediate part of the very narrow groove part3, whereby the thin-film magnetic head 300A in accordance with thepresent invention (see FIG. 1) is obtained.

As explained in detail in the foregoing, the even width portion 12molded by the very narrow groove part 3 is formed in the magnetic poletip 11 of the main magnetic pole layer 10. Therefore, when theintermediate portion of the very narrow groove part 3 is cut so as toform the ABS 30 in the manufacturing of the thin-film magnetic head, themain magnetic pole layer 10 is cut at the even width portion 12 of themagnetic pole tip 11. Since the even width portion 12 has an even width(i.e., W1 does not change throughout the length), the width W1 of themagnetic pole tip 11′ (i.e., track width) appearing in the cross section(ABS 30) does not vary even when the cut position fluctuates within thearea where the even width portion 12 extends.

In conventional magnetic head structures in which the width of themagnetic pole tip is not sufficiently even, the width of the magneticpole tip appearing in the ABS may vary when the position to cut the ABSfluctuates, whereby the track width may vary among products. When thethin-film magnetic head structure 300 including the even width portion12 in the magnetic pole tip 11 is used for making a thin-film magnetichead, by contrast, the thin-film magnetic head in which the track widthis controlled with a high accuracy can be obtained.

Method of Manufacturing Thin-Film Magnetic Head

With reference to FIGS. 5, 6, 8, 9 and 11 to 13 in addition to FIGS. 1to 4 mentioned above, a method of manufacturing the thin-film magnetichead structure 300 having the above-mentioned configuration will beexplained.

FIGS. 5, 6, 8, and 9 are plan or sectional views in respective steps ofthe manufacturing method, in which FIGS. 5A, 6A, 8A and 9A are planviews, and FIGS. 5B, 6B, 8B and 9B are sectional views taken along theline B-B of FIGS. 5A, 6A, 8A and 9A, respectively. FIGS. 5C, 6C, 8C and9C are plan views showing a major part of FIGS. 5A, 6A, 8A and 9A,respectively, under magnification, and FIGS. 5D, 6D, 8D and 9D aresectional views taken at the Abs 30 of FIGS. 5B, 6B, 8B and 9B,respectively. FIGS. 11 to 13 are plan or sectional views in respectivesteps of the manufacturing method, in which FIGS. 11A, 12A and 13 A aresectional views taken along a plane orthogonal to the ABS, whereas FIGS.1B, 12B and 13B are sectional views taken at the ABS 30 in FIGS. 11A,12A and 13A.

First, for making the thin-film magnetic head structure 300, areproducing head structure comprising an MR device (magnetoresistivedevice) and the like is laminated on an undepicted substrate made ofaluminum oxide titanium carbide (Al₂O₃.TiC), for example. Subsequently,an insulating layer 1 is formed from alumina (Al₂O₃) or a nonmagneticmaterial.

After a photoresist is applied onto the insulating layer 1, patterningis performed with a predetermined photomask, so as to form a resistpattern exposing the surface of the insulating layer 1 into a formcorresponding to the cavity 2. Using this resist pattern as a mask,reactive ion etching (hereinafter referred to as “RIE”) is carried out,so as to remove the part of insulating layer 1 not covered with theresist pattern, whereby the cavity 2 is formed as shown in FIGS. 2A and2B, and FIGS. 5A, 5B, 5C and 5D.

Next, as shown in FIG. 6, a coating 16 is formed on the whole surface ofthe insulating layer 1. As shown in FIG. 7, the coating 16 has athree-layer structure in which an Al₂O₃ layer 16 a, a Ta layer 16 b, anda seed layer 16 c are laminated successively from the side closer to theinsulating layer 1. The Al₂O₃ layer 16 a and the Ta layer 16 b areformed in order to control dimensions (width and depth) of the verynarrow groove part 3 formed by the RIE. The Al₂O₃ layer 16 a and the Talayer 16 b are laminated by ALCVD and sputtering, respectively, so as toyield a thickness of about 200 to 500 Å in total. The seed layer 16 c isused for plating the cavity 2 with a magnetic material, and is formed bya thickness of about 400 Å by sputtering or IBD (ion beam deposition).Since the Ta layer 16 can also be used as a seed layer at the time ofplating with the magnetic material, the seed layer 16 c can be omittedas appropriate.

As shown in FIG. 8, a magnetic layer 26 made of CoNiFe which is amagnetic material having a high saturated magnetic flux density (on theorder of 2.3 T to 2.4 T) is formed by plating on the seed layer 16 c ofthus formed coating 16. The magnetic layer 26 has a thickness of about0.7 μm, and will later become the main magnetic pole layer 10.

Subsequently, as shown in FIGS. 9 and 10, the whole surface of thesubstrate including the surface of the magnetic layer 26 on the sidecloser to the thin-film coil 100 is subjected to chemical mechanicalpolishing (hereinafter referred to as “CMP”) which will end at thesurface of the Ta layer 16 b in the coating 16, so as to flatten thesurface of the magnetic layer 26. As a consequence, the main magneticpole layer 10 is formed so as to be embedded in the cavity 2. When theTa layer 16 b formed near the very narrow groove part 3 is used fordetecting the end point of CMP as such, the amount of polishing near thevery narrow groove part 3 can be adjusted with a high accuracy. Namely,the height of the magnetic pole tip 11 highly accurately coincides withthe depth of the cavity 2 covered with the coating 16.

After the surface flattening, a recording gap layer 24, a first shieldpart 41, a back magnetic pole layer 51, and an insulating layer 31 areformed as shown in FIGS. 11A and 11B.

More specifically, a coating 34 for forming the recording gap layer 24is formed by a thickness of 400 to 500 Å so as to cover the whole upperface of the substrate including the magnetic pole tip 11 and yokemagnetic pole part 20. The material of the coating 34 may be either aninsulating material such as alumina or a nonmagnetic metal material suchas Ru, NiCu, Ta, W, Cr, Al₂O₃, Si₂O₃, or NiPd. The coating 34 will laterform the recording gap layer 24. Subsequently, while opening the coating34 in areas where the first shield part 41 and the back magnetic polelayer 51 are to be formed, the first shield part 41 and the backmagnetic pole layer 51 are formed. In this case, the first shield part41 is formed so as to oppose the magnetic pole tip 11 by way of therecording gap layer 24 in order to determine the neck height NH. Theback magnetic pole layer 51 is formed so as to join with the yokemagnetic pole part 20 at a position not covered with the recording gaplayer 24. It will be sufficient if the first shield part 41 and the backmagnetic pole layer 51 are formed by plating with CoNiFe or NiFe as amagnetic material as with the yoke magnetic pole part 20. Next, theinsulating layer 31 made of alumina (Al₂O₃) is formed by a thickness of1.0 μm to 1.5 μm, for example, so as to cover the whole upper face ofthe substrate.

Subsequently, in order for the first shield part 41 and the yokemagnetic pole part 20 to have a thickness on the order of 0.5 μm to 1.0μm, their surface is subjected to CMP as a surface-flattening process.This forms an opening in a place where a second shield part 42 is to beformed. Then, as shown in FIG. 12, an electrode film (not depicted) madeof a conductive material and a frame made by photolithography are formedon the insulating layer 31, and then electroplating is performed withthe electrode film, so as to form a plating layer made of Cu. Thisplating layer and the electrode film thereunder become a thin-film coil100. The thin-film coil 100 is formed on the yoke magnetic pole part 20by way of the insulating layer 31.

Next, though not depicted, a frame is formed by photolithography, andthe second shield part 42 is formed by frame plating. The second shieldpart 42 uses the same magnetic material as with the first shield part41. The second shield part 42 and the thin-film coil 100 may be formedin reverse order as well.

Subsequently, a photoresist 101 is applied so as to cover the wholeupper face of the substrate. Further, an insulating layer 35 made ofalumina (Al₂O₃) is formed by a thickness of about 3.0 μm to 4.0 μmthereon, and then the whole surface is subjected to CMP as asurface-flattening process (see FIG. 13).

Subsequently, an insulating layer made of alumina (Al₂O₃) is formed by athickness of about 0.2 μm so as to cover the whole upper face of thesubstrate, and an opening is formed in the place where the second shieldpart 42 is formed. This yields an insulating layer 32 which insulatesthe thin-film coil 100 and a third shield part 43 from each other so asto prevent them from short-circuiting. Finally, the third shield part 43is formed by a thickness of about 2 μm to 3 μm, whereby the write shieldlayer 40 is formed. The foregoing steps yield the thin-film magnetichead structure 300 shown in FIGS. 1A and 1B.

The process of the cavity 2 covered with the coating 16 being filledwith the magnetic layer 26 will now be explained with reference to FIGS.14, 15, and 16.

When the forming of the magnetic layer 26 by plating is started from thestate where the cavity 2 is formed with the coating 16 (the state shownin FIG. 6), the magnetic layer 26 gradually grows from the surface ofthe seed layer 16 c of the coating 16 formed on the bottom and innerside faces of the cavity 2. Here, in the plating material (magneticmaterial) grown on the inner side face of the variable width depression4 and protruded depression 6 (see FIG. 2), portions in the vicinity ofthe very narrow groove part 3 (see the circle C defined by adash-single-dot line in FIG. 14) abut against each other, therebyentering the very narrow groove part from both sides thereof as shown inFIGS. 14 and 15. The arrow in FIG. 14 indicates the growing direction ofanisotropically growing magnetic material crystals 26 a. Thus, as shownin FIG. 15, the very narrow groove part 3 is filled with the portion ofplating material grown therewithin and the portions of plating materialgrown in the variable width depression 4 and protruded depression 6 onboth sides thereof. When the forming of the film by plating furtheradvances, the magnetic layer 26 entering the very narrow groove part 3from the variable width depression 4 and protruded depression 6 fillsthe very narrow groove part 3 without gaps as shown in FIG. 16.

The bottom area of the very narrow groove part 3 is smaller than that ofthe variable width depression 4 or protruded depression 6. Therefore,when the film is uniformly formed by plating on the seed layer 16 c, themagnetic layer 26 formed on the very narrow groove part 3 becomesthicker than that formed in the other regions (i.e., the variable widthdepression 4, protruded depression 6, and fixed width depression 5)within the cavity 2. Further performing the forming of the film byplating yields the magnetic layer 26 filling the whole cavity 2 (seeFIG. 8).

When the very narrow groove part 3 is too long, the magnetic layer 26does not fully travel by way of both sides of the very narrow groovepart 3 as mentioned above, thus generating a keyhole 15 in the magneticpole tip 11′ corresponding to the very narrow groove part 3 as shown inFIG. 17. The keyhole 15 extends along the magnetic pole tip 11′ and hasa substantially V-shaped cross section. Studies conducted by theinventors have elucidated that the keyhole 15 is not generated when thevery narrow groove part 3 has a length of 1.2 μm or less. Since thecoating 16 covering the very narrow groove part 3 is so thin that itsthickness is negligible with respect to the length and width of the verynarrow groove part 3, the length and width of the very narrow groovepart 3 are substantially equal to those of the even width portion 12,respectively.

Namely, in order for the plating material grown in the variable widthdepression 4 and protruded depression 6 to enter the very narrow groovepart 3 so that the latter is more reliably filled with the platingmaterial, it will be preferred if the length of the very narrow groovepart 3 (i.e., the length of the even width portion 12) is 1.2 μm orshorter (e.g., 0.8 μm). However, since the ABS is harder to cut when thelength of the very narrow groove part 3 is less than 0.3 μm, it will bepreferred if the very narrow groove part 3 has a length of at least 0.3μm. In order for the length to be automatically measurable with CD-SEM,it will be more preferred if the very narrow groove part 3 has a lengthof at least 0.5 μm. When the width of the very narrow groove part 3(i.e., the width of the even width portion 12) is 0.2 μm or less, theplating material is less likely to grow within the very narrow groovepart 3. Therefore, the very narrow groove part having a length of 1.2 μmor less is quite effective in filling the narrow groove part 3 with theplating material without gaps.

The manufacturing method explained in the foregoing reliably forms themain magnetic pole layer 10 having the even width portion 12. Therefore,when the thin-film magnetic head structure 300 made by thismanufacturing method is used for making a thin-film magnetic head, thethin-film magnetic head can be obtained with a highly accuratelycontrolled track width.

In order to for the ABS-side portion of the magnetic pole tip in themain magnetic pole layer to be formed like a bevel, the followingprocedure has been employed in conventional PMRs. Namely, in theconventional PMRs, there has been a case where, as shown in FIG. 18A, amain magnetic pole layer 501 formed on an insulating layer 500 is formedwith an insulating layer 502 made of alumina, and is subjected to ionbeam etching (hereinafter referred to as “IBE”) by direct irradiationwith ion beams P. In this case, the speed at which the insulating layer500 is etched by the IBE varies depending on the ion beam irradiation.Namely, depending on the distance from the beam center, barriers (e.g.,the variable width region 21 of the above-mentioned yoke magnetic polepart 20) inhibiting the magnetic pole tip from being irradiated with thebeams, etc., there have been respective portions with higher and loweretching speeds. Therefore, a main magnetic pole layer including amagnetic pole tip having an even width has not been obtained by anymeans. Hence, as mentioned above, the width of the magnetic pole tipappearing in the ABS may vary when the position to cut the ABSfluctuates, whereby the track width may vary among products.

Also, in the conventional PMRs, the etching speed by the IBE is slowerin the magnetic pole tip in the main magnetic pole layer 501 than in theinsulating layer 500, whereby the IBE must be performed for a long timein order for the magnetic pole tip to attain a bevel form. As aconsequence, the ABS-side portion of the magnetic pole tip tends to havea form including a narrowed part 501 a having a smaller diameter asshown in FIG. 18B.

In addition, even when the main magnetic pole layer 501 is intended tobe formed as shown in FIG. 19A, a rear end portion (flare point) of anarrow band part 501 b having a width corresponding to the track widthmay retract as shown in FIG. 19B, so as to yield a flare point, therebymaking the neck height NH longer than its expected length (about 0.15μm) by d (about 0.2 μm to 0.3 g/m). In general, the position at whichthe magnetic pole tip of the main magnetic pole layer is cut isdetermined by the distance from the above-mentioned flare point, so thatthe position of the flare point is hard to specify when an edge of theflare point retracts or is shaven, whereby the track width may shift.Also, such conventional PMRs have been hard to increase the quantity ofmagnetization in places near the ABS 503, which makes it difficult toyield a favorable overwrite characteristic (a characteristic by whichdata recorded on a recording medium is overwritten with another data).

The magnetic pole tip in the main magnetic pole layer 501 hasconventionally been formed by plating using photolithography. In orderfor the ABS-side portion to have a bevel form, a resist pattern 504having a taper angle as shown in FIG. 20A and a seed layer 505interposed between the resist pattern 504 and the insulating layer 500may be used. When the track width is to be narrowed in order to improvethe recording density in this case, the ion beams P must be emittedafter removing the resist pattern 504 as shown in FIG. 20B, so as toperform trimming with the IBE for a long time. As a result, the mainmagnetic pole layer including the magnetic pole tip having an even widthcannot be obtained because of the problem of IBE etching speed mentionedabove.

When plating is performed with a resist pattern having a narrow widthprepared beforehand as shown in FIG. 21A and FIG. 21B, on the otherhand, the exposed surface of the seed layer 505 becomes narrower,whereby the seed layer 505 fails to supply electricity to the groovepart defined by the resist pattern to such an extent that the mainmagnetic pole layer 501 grows sufficiently. Also, when the magnetic poletip of the main magnetic pole layer 501 having a narrow width issubjected to the IBE, there is a fear of the formed magnetic pole tipfalling down.

Thus, when the width of the magnetic pole tip is to be narrowed in orderto improve the recording density in the conventional PMRs, the widthmust become uneven.

By contrast, the thin-film magnetic head structure 300 in thisembodiment includes the insulating layer 1 provided with the cavity 2,in which the main magnetic pole layer 10 is embedded, and thus caneliminate all of the foregoing problems.

Namely, since the cavity 2 is sunken into a form corresponding to theouter form of the main magnetic pole layer 10, the main magnetic polelayer 10 can be formed in the shape and dimensions as set. Since thetrack width is determined by the very narrow groove part 3 of the cavity2, there is no need to perform IBE for a long time at all in order forthe magnetic pole tip to have a bevel form. Therefore, the neck heightcan be set to a value as assumed, the quantity of magnetism in placesnear the ABS 403 can be enhanced, and a thin-film magnetic head having afavorable overwrite characteristic can be manufactured.

The track width can be narrowed if the width of the very narrow groovepart 3 is reduced as much as possible, whereas the very narrow groovepart 3 can set the track width to a value assumed. Therefore, not onlythe track width is narrow, but also the dimensional accuracy and yieldbecome favorable, and there is no fear of the formed magnetic pole tipfalling down. Therefore, providing the cavity 2 as in the thin-filmmagnetic head structure 300 can reliably form the main magnetic polelayer having an enhanced recording density.

The main magnetic pole layer 10 in the thin-film magnetic head inaccordance with the present invention can have a joint structure by thefollowing manufacturing method. Namely, the supply of the magneticmaterial to become the magnetic layer 26 is terminated when the narrowgroove 3 is completely filled with the magnetic layer 26 as shown inFIG. 22 (in the state shown in FIG. 16). Here, the magnetic layer 26 hasan in-depression end face 26 a exposed into a region other than the verynarrow groove part 3 in the cavity 2, and thus is the end-face-equippedmagnetic pole layer in the present invention. Then, a magnetic materialhaving a saturated magnetic flux density (on the order of about 1.9 to2.1 T) lower than that of the magnetic material constituting themagnetic layer 26 is started to be supplied. This yields a state wherethe magnetic layer 26 is formed on the surface of the inner side face ofthe cavity 2 and in the very narrow groove part 3, whereas the partother than the very narrow groove part 3 in the cavity 2 is filled witha magnetic layer 27 having a thickness of about 1.0 μm (see FIG. 22A).

In this case, the magnetic layer 27 joins with the in-depression endface 26 a of the magnetic layer 26 within the cavity 2, whereby theirjoint becomes an interface 28. Namely, the magnetic layer 27 is thejoining magnetic layer in the present invention, and will later form ayoke magnetic pole part 20A′. The interface 28 will later become aninterface 14. Further, on the outer part of the insulating layer 1 inthe whole surface of the substrate, an insulating layer 29 made ofalumina (Al₂O₃) is formed by a thickness on the order of 0.5 μm to 1.0μm (see FIG. 22B).

Subsequently, using the Ta layer 16 b of the coating 16 as a stopperlayer, the whole surface of the substrate including the surface of themagnetic layers 26 and 27 on the side closer to the thin-film coil 100is subjected to CMP as a surface-flattening process (see FIG. 22C). Thisyields a main magnetic pole layer 10A′ as shown in FIG. 23.

As shown in FIG. 23, the main magnetic pole layer 10A′ comprises amagnetic pole tip 11A′ and the yoke magnetic pole part 20A′, whereas itssurface on the side closer to the thin-film coil 100 has a stepless flatstructure as in the main magnetic pole layer 10′ shown in FIG. 4. FIG.23 is a view showing the main magnetic pole layer 10A′ after being cutalong the ABS 30, in which FIG. 23A is a perspective view, and FIG. 23Bis a sectional view taken along the line B-B of FIG. 23A. FIG. 24 is aplan view showing the main magnetic pole layer 10A′. The main magneticpole layer 10A′ has an end face joint structure in which respective endfaces of the magnetic pole tip 11A′ and yoke magnetic pole part 20A′extending along the ABS 30 are joined to each other in a region(variable width depression 4) other than the very narrow groove part 3in the cavity 2. The joint between the end faces forms the interface 14.

The magnetic pole tip 11A′ is disposed at a position closer to the ABS30 than is the yoke magnetic pole part 20A′. The magnetic pole tip 11A′is constituted by a uniform width part 12 defining the track width ofthe thin-film magnetic head in the present invention, and a variablewidth part 13 having a variable width structure whose width extendingalong the ABS 30 gradually increases in the direction away from the ABS30. The even width portion 12 extends in a direction intersecting theABS 30 and has an even width of 0.1 μm in the extending direction of themagnetic pole tip 11′. The distance D2 from the ABS 30 to the rear endportion of the magnetic pole tip 11A′ is shorter than the distance D1from the ABS 30 to the rear end portion of the yoke magnetic pole part20A′, whereby the magnetic pole tip 11A′ has a shortened structure so asnot to connect with the write shield layer 40.

For enhancing the density at which data is recorded by the thin-filmmagnetic head, the magnetic head tip 11A′ has a narrow track widthstructure in which the width W1 is reduced as in the magnetic pole tip11′. The magnetic pole tip 11A′ uses a magnetic material (Hi-Bsmaterial) having a saturated magnetic flux density higher than that ofthe yoke magnetic pole part 20A′ so as not to be saturated with magneticfluxes even in the narrow track width structure. The magnetic pole tip11A′ and yoke magnetic pole part 20A′ are magnetized such that thedirection of magnetization ms aligns with the ABS 30 (see FIG. 24).

Known as an example of the conventional PMRs is a thin-film magnetichead 400 having a structure shown in FIGS. 25A, 25B and 25C. Thisthin-film magnetic head 400 includes a main magnetic pole layer 402which is formed on an insulating layer 401 and has a bevel-shapedmagnetic pole tip disposed on the side of an ABS 403; a write shieldlayer 405 which is magnetically connected to the main magnetic polelayer 402 and opposes the main magnetic pole layer 402 by way of arecording gap layer 404 on the ABS 403 side; and a thin-film coil 406.The thin-film coil 406 is wound in a planar spiral about a junction 408connecting the main magnetic pole layer 402 and the write shield layer405, while its windings are insulated from each other by a photoresist407. In the conventional PMRs, as in the thin-film magnetic head 400, amagnetic material is magnetized such that the direction of magnetizationms is oriented so as to extend along the ABS 403, whereby the mainmagnetic pole layer 402 is formed.

In the conventional PMRs such as the thin-film magnetic head 400,however, even when the direction of magnetization ms is oriented so asto extend along the ABS 403, the direction of remnant magnetization mrinside the main magnetic pole layer 402 after completion of writing isoriented toward the ABS 403 side and thus faces a different directionthan the magnetization ms. (The direction different from that extendingalong the ABS will be referred to as “different direction” in thefollowing.) Therefore, when such a PMR writes data, leakage magneticfluxes due to the remnant magnetization mr may erase data alreadywritten on a hard disk or weaken signals of written data even though nowrite current is flowing.

Namely, since the main magnetic layer 402 is formed from the samemagnetic material from the ABS 403 to the end part on the opposite sideby way of the thin-film coil, the remnant magnetization is directed tothe ABS 403 in the conventional PMRs. In the thin-film magnetic headstructure 300 comprising the main magnetic pole layer 10A having the endface joint structure constituted by two magnetic poles, i.e., themagnetic pole tip 11A and yoke magnetic pole part 20A, by contrast, theinterface 14 formed by the end face junction between the magnetic poletip 11A and yoke magnetic pole part 20A blocks the emission of remnantmagnetization mr₂₀ from the yoke magnetic pole part 20A to the magneticpole tip 11A. As a consequence, the thin-film magnetic head structure300 can make a thin-film magnetic head with reduced remnantmagnetization mr directed to the ABS 30. Even when the materialconstituting the main magnetic pole layer 10A and the materialconstituting the yoke magnetic pole part 20A are the same, the end facejoint structure can be formed, whereby the pole erasure can be preventedfrom occurring.

Since the magnetic pole tip 11A is made smaller than the yoke magneticpole part 20A, such that the yoke magnetic pole part 20A has a size(area) greater than that of the magnetic pole tip 11A, the quantity ofmagnetization (also known as magnetic volume) of the yoke magnetic polepart 20A is greater than that of the magnetic pole tip 11A. However, theinterface 14 blocks the emission of remnant magnetization from the yokemagnetic pole part 20A having a greater quantity of magnetization, sothat the emission of remnant magnetization decreases drastically,whereby the pole erasure is more effectively prevented from occurring.

Further, as explained with reference to FIG. 14, the direction ofcrystallization of the magnetic crystals 26 b in the magnetic bodygrowing on the inner side face of the very narrow groove part 3 isoriented in a direction traversing the very narrow groove part 3.Namely, the direction of crystallization and the direction of magneticfield (i.e., the extending direction of the very narrow groove part 3)in the even width portion 12 formed within the very narrow groove part 3are orthogonal to each other. The inventors have newly found that theoccurrence of the pole erasure can be suppressed more effectively whenthe direction of crystal growth of the magnetic crystals 26 b and thedirection of magnetic field within the even width portion 12 in the mainmagnetic pole layer 10 have such a relationship therebetween.

Meanwhile, in the case of a conventional PMR, the main magnetic polelayer is preferably a magnetic material with a small maximum coercivityHc (about 2-10 Oe) and a small magnetostriction λ (1-3×10⁻⁶), while itis also preferably a magnetic material with a small magnetostriction λin order to eliminate the aforementioned pole erasure.

However, in order to avoid impairment in the overwrite characteristicwhich occurs with flux saturation even if the track width is narrowed toimprove the recording density, the magnetic material of the mainmagnetic pole layer is preferably formed of a magnetic material with ahigh saturated flux density, but when this is done it becomes difficultto lower the magnetostriction λ of the main magnetic pole layer. In viewof this point, the above-mentioned thin-film magnetic head structure 300forms the main magnetic pole layer 10A as a joint structure made of themagnetic pole tip 11A and yoke magnetic pole part 20A having respectivesaturated magnetic flux densities different from each other, while thesaturated magnetic flux density of the yoke magnetic pole part 20A ismade lower than that of the magnetic pole tip 11A, so as to reduce themagnetostriction λ of the yoke magnetic pole part 20A. This makes themain magnetic pole layer 10A reduce the magnetostriction λ as a whole.Hence, using the thin-film magnetic head structure 300 yields athin-film magnetic head which can more effectively prevent the poleerasure from occurring.

MODIFIED EXAMPLES

Without being restricted to the above-mentioned embodiment, the presentinvention can be modified in various manners.

Modified Example 1

The above-mentioned manufacturing process of the thin-film magnetic headstructure can be modified as follows. Namely, after the whole upper faceof the substrate is subjected to CMP as explained with reference toFIGS. 12A and 12B, the thin-film coil 100 is formed by way of theinsulating layer 31 earlier than the second shield part 42.Subsequently, the photoresist 101 is formed so as to cover the thin-filmcoil 100. Further, the second shield part 42 is formed so as to coverthe thin-film coil 100 and the photoresist 101, and connect with thefirst shield part 41 and the back magnetic pole layer 51. This yields athin-film magnetic head structure 301 including the write shield layer40 comprising the first shield part 41 and second shield part 42 withoutthe third shield part 43 as shown in FIGS. 26A and 26B.

This thin-film magnetic head structure 301 has the same configuration aswith the thin-film magnetic head structure 300 except that it lacks thethird shield part 43 and the insulating layer 32. Therefore, thethin-film magnetic head structure 301 exhibits the same operations andeffects as with the thin-film magnetic head structure 300. Themanufacturing process in this modified example requires no step formanufacturing the third shield part 43, and thus can become simpler thanthe manufacturing process of the thin-film magnetic head structure 300.

Modified Example 2

A nonmagnetic film 61 may be interposed between the magnetic pole tip11A and yoke magnetic pole layer 20A forming the above-mentioned endface junction as in a thin-film magnetic head structure 310 shown inFIG. 27. The nonmagnetic film 61 is formed in a portion of the yokemagnetic pole part 20 other than its surface on the thin-film coil 100side. Namely, the nonmagnetic film 61 is disposed at the interface 14between the magnetic pole tip 11 and the yoke magnetic pole part 20, andin the portion between the yoke magnetic pole part 20 and the coating16. The nonmagnetic film 61 is made of Ru, Ta, W, Cr, NiPd, or the likeand has a thickness of about 10 to 30 Å.

The nonmagnetic film 61 functions to control the direction of remnantmagnetization mr in the magnetic pole tip 11 and yoke magnetic pole part20 and prevent the direction of remnant magnetization mr from beingoriented in a different direction. Therefore, the thin-film magnetichead structure 310 can more effectively prevent the pole erasure fromoccurring, while improving the recording density more than the thin-filmmagnetic head structure 300 does.

Modified Example 3

An upper yoke magnetic pole part 45 may be provided as appropriate as ina thin-film magnetic head structure 320 shown in FIG. 28. The thin-filmmagnetic head structure 320 includes the upper yoke magnetic pole part45, which is joined to the surface of the yoke magnetic pole part 20 onthe side closer to the thin-film coil 100 at a position distant from theABS 30 than is the recording gap layer 24. The upper yoke magnetic polepart 45 is formed together with the first shield part 41 when the firstshield part 41 is formed by plating.

Joining the upper yoke magnetic pole part 45 to the yoke magnetic polepart 20 can increase the quantity of magnetization of the main magneticpole layer 10 in the vicinity of the ABS 30. Therefore, the thin-filmmagnetic head structure 320 can manufacture a thin-film magnetic headhaving a favorable overwrite characteristic. When manufacturing thethin-film magnetic head structure 320, it will be sufficient if the stepof joining the upper yoke magnetic pole part 45 to a part distant fromthe ABS 30 than is the recording gap layer 24 in the yoke magnetic polepart 20 is further provided.

Modified Example 4

Similarly, a lower yoke magnetic pole part 46 may be provided asappropriate as in a thin-film magnetic head structure 330 shown in FIG.29. The thin-film magnetic head structure 330 includes the lower yokemagnetic pole part 46, which is joined to the surface of the yokemagnetic pole layer 20A at a position opposing the thin-film coil 100 byway of the yoke magnetic pole part 20. The lower yoke magnetic pole part46 is formed in the stage of forming the cavity 2 by using a knownphotolithography technique.

Joining the lower yoke magnetic pole part 46 to the yoke magnetic polepart 20 can increase the quantity of magnetization of the main magneticpole 10 in the vicinity of the ABS 30 as with the above-mentioned upperyoke magnetic pole layer 45. Therefore, the thin-film magnetic headstructure 330 can manufacture a thin-film magnetic head having afavorable overwrite characteristic.

Modified Example 5

The form of the cavity 2 provided in the above-mentioned thin-filmmagnetic head structures 300, 301, 310, 320, 330 is not limited to theform shown in FIG. 2, but may be changed to those shown in FIGS. 30 to35 and the like as appropriate.

The cavity 2A shown in FIG. 30 differs from the cavity 2 shown in FIG. 2in that the variable width depression 4 is constituted by two stages ofvariable width depressions 4 a, 4 b having respective flare anglesdifferent from each other. The cavity 2B shown in FIG. 31 differs fromthe cavity 2 shown in FIG. 2 in that the variable width depression 4 isconstituted by two stages of variable width depressions 4 a, 4 b havingrespective flare angles different from each other, and that theprotruded depression 6 is constituted by a variable width depression 6 aand a fixed width depression 6 b. The cavity 2C shown in FIG. 32 differsfrom the cavity 2 shown in FIG. 2 in that the variable width depression4 is constituted by two stages of variable width depressions 4 a, 4 bhaving respective flare angles different from each other, and that theprotruded depression 6 is constituted by two stages of variable widthdepressions 6 a, 6 b having respective flare angles different from eachother. The cavity 2D shown in FIG. 33 differs from the cavity 2 shown inFIG. 2 in that the protruded depression 6 is constituted by a variablewidth depression 6 a and a fixed width depression 6 b.

In the cavity 2E shown in FIG. 34, the depression corresponding to theyoke magnetic pole layer 20 is constituted by two stages of variablewidth depressions 4 a, 4 b having respective flare angles different fromeach other, and a fixed width depression 4 c. In the cavity 2F shown inFIG. 35, the depression corresponding to the yoke magnetic pole layer 20is constituted by two stages of variable width depressions 4 a, 4 bhaving respective flare angles different from each other with respectivewidths different from each other at their boundary position. Namely, atthe boundary position between the variable width depressions 4 a and 4b, the width of the variable width depression 4 b is greater than thatof the variable width depression 4 a. Though FIGS. 30 to 35 exemplifyflare angles, these angles are not restrictive.

It is not always necessary for the above-mentioned thin-film magnetichead structures 300, 301, 310, 320, 330 to be manufactured with thecavity 2, and their manufacturing method can be changed to knownphotolithography techniques as appropriate. The end face of the magneticpole tip does not necessarily have a bevel form, but may have any knownend face form. The width of the even width portion in the magnetic poletip is not limited to 0.1 μm, but may appropriately be increased ordecreased as long as it is not greater than 0.2 μm.

It is apparent that various embodiments and modifications of the presentinvention can be embodied, based on the above description. Accordingly,it is possible to carry out the present invention in the other modesthan the above best mode, within the following scope of claims and thescope of equivalents.

1. (canceled)
 2. A thin-film magnetic head structure adapted tomanufacture a thin-film magnetic head, comprising: a configuration of amain magnetic pole layer including a magnetic pole tip on a side of amedium-opposing surface opposing a recording medium, a write shieldlayer opposing the magnetic pole tip so as to form a recording gap layeron the medium-opposing surface side, and a thin-film coil wound aboutthe write shield layer or the main magnetic pole layer are laminated; abase insulating layer including a magnetic pole forming depressionsunken into a form corresponding to the main magnetic pole layer, themagnetic pole forming depression including a very narrow groove parthaving a substantially even width, the even width portion being formedin the very narrow groove part of the magnetic pole forming depression,wherein the magnetic pole tip of the main magnetic pole layer includesan even width portion having a substantially even width along anextending direction intersecting the medium-opposing surface, whereinthe thin film coil is disposed outside of the magnetic pole formingdepression of the base insulating layer.
 3. A thin-film magnetic headstructure according to claim 2, wherein the magnetic pole formingdepression includes a pair of variable width depressions continuouslyextending from respective end parts of the very narrow groove part, eachof the variable width depressions having a width increasing in adirection away from the very narrow groove part; and wherein the verynarrow groove part has such a width and length that a plated materialgrown in the variable width depression when forming the main magneticpole layer by plating within the magnetic pole forming depression fillsthe very narrow groove part without a gap.
 4. A thin-film magnetic headstructure according to claim 3, wherein the even width portion has alength of 0.3 μm to 1.2 μm along the extending direction thereof.
 5. Athin-film magnetic head structure according to claim 3, wherein the evenwidth portion has a width of 0.2 μm or less.
 6. A thin-film magnetichead structure according to claim 2, wherein the main magnetic polelayer has an end face joint structure where respective end faces of themagnetic pole tip and a yoke magnetic pole part having a size greaterthan that of the magnetic pole tip are joined to each other.
 7. Athin-film magnetic head structure according to claim 2, wherein the verynarrow groove part is formed such that a groove width intersecting thelength thereof gradually decreases along the depth thereof. 8.(canceled)
 9. (canceled)
 10. (canceled)
 11. (canceled)
 12. (canceled)12. (canceled)
 13. A thin-film magnetic head structure according toclaim 2, wherein the magnetic pole forming depression is formed byreactive ion etching (RIE).
 14. A thin-film magnetic head, comprising: aconfiguration of a main magnetic pole layer including a magnetic poletip on a side of a medium-opposing surface opposing a recording medium,a write shield layer opposing the magnetic pole tip so as to form arecording gap layer on the medium-opposing surface side, and a thin-filmcoil wound about the write shield layer or the main magnetic pole layerare laminated; a base insulating layer including a magnetic pole formingdepression sunken into a form corresponding to the main magnetic polelayer, the magnetic pole forming depression including a very narrowgroove part having a substantially even width, the even width portionbeing formed in the very narrow groove part of the magnetic pole formingdepression, wherein the magnetic pole tip of the main magnetic polelayer includes an even width portion having a substantially even widthalong an extending direction intersecting the medium-opposing surface,wherein the thin film coil is disposed outside of the magnetic poleforming depression of the base insulating layer.